New to the forum, but not to Squarebodies...

[CapAhab]

Nice truck i must say

 

[Donald vonMinden]

I grew up with Squarebody Chevies, as my dad had 3 or 4 of them over the years; I even learned to drive in a '75 1/2 ton 4X4 manual hauling hay bales. After about 20 years without one around, I recently bought an almost entirely cancer-free '78 Scottsdale K20 for my daily driver. Mildly built 350 w/ 4 bbl Quadrajet, TH400, NP203, and 4:56 gears!! Low, low!! I also have the build sheet, and it's almost entirely stock. Factory A/C (missing a bunch of parts, including the compressor), cruise control (transducer is there, but missing the rest), and the HC4 4:56 gears. The underside of this beast looks new!!
I could use some advice from you squareheads on a couple of things:
1. I know the gears came with the truck, since they are on the build sheet. I looked the truck up on the build option chart posted elsewhere on this forum, and it would appear that they must have been special ordered, as the charts say that gear ratio was only offered stock on the K30 one-tons. Since they were put on this truck by Chevy, does that mean that other rear-end components were likely beefed up as well, or could the 4:56 gears just be paired up with the standard 3/4 ton axles, etc.? I ask because I may want to swap both front and rear gear sets to 4:10s at some point in the future, but I'm not sure what all I will need to do that.
2. Come next summer, I will want to get the A/C working, and I ordered the whole OEM style shooting match from LMC to have on hand when the time comes. LMC did not offer all of the lines, however, as you can see in the attached diagram circled in red. Can you guys tell me what that part is and where I might locate it?
3. I also have no idea which compressor to get. I've never had one of these trucks with A/C in it, so I don't know what I am looking for. Is there one out there that uses the newest refrigerant, or are they all R134A?

Thanks a lot for your help in advance!!

Tim

PS - Yes, I know the grille is not the right one for that truck - it's already been swapped out with the right one, just haven't taken a new pic yet!!

I have a 1977 K10 and it came with the Frigidaire Axial compressor, and R12. A few years later came the R134A refrigerants.......

 

[Donald vonMinden]

I have a 1977 K10 and it came with the Frigidaire Axial compressor, and R12. A few years later came the R134A refrigerants.......

On the LMC AC diagram above is drawn a picture of the Frigidaire model.

 

[Donald vonMinden]

Yes, there are better compressors available that are more efficient with current refrigerants. Sometimes I get swayed by my inclination to RESTORE rather than Modify.....LOL

 

[squaredeal91]

There's a brand of refrigerant that's safe to add to existing R12 to top off. I think it was called red tech.

 

[ButchM]

I grew up with Squarebody Chevies, as my dad had 3 or 4 of them over the years; I even learned to drive in a '75 1/2 ton 4X4 manual hauling hay bales. After about 20 years without one around, I recently bought an almost entirely cancer-free '78 Scottsdale K20 for my daily driver. Mildly built 350 w/ 4 bbl Quadrajet, TH400, NP203, and 4:56 gears!! Low, low!! I also have the build sheet, and it's almost entirely stock. Factory A/C (missing a bunch of parts, including the compressor), cruise control (transducer is there, but missing the rest), and the HC4 4:56 gears. The underside of this beast looks new!!
I could use some advice from you squareheads on a couple of things:
1. I know the gears came with the truck, since they are on the build sheet. I looked the truck up on the build option chart posted elsewhere on this forum, and it would appear that they must have been special ordered, as the charts say that gear ratio was only offered stock on the K30 one-tons. Since they were put on this truck by Chevy, does that mean that other rear-end components were likely beefed up as well, or could the 4:56 gears just be paired up with the standard 3/4 ton axles, etc.? I ask because I may want to swap both front and rear gear sets to 4:10s at some point in the future, but I'm not sure what all I will need to do that.
2. Come next summer, I will want to get the A/C working, and I ordered the whole OEM style shooting match from LMC to have on hand when the time comes. LMC did not offer all of the lines, however, as you can see in the attached diagram circled in red. Can you guys tell me what that part is and where I might locate it?
3. I also have no idea which compressor to get. I've never had one of these trucks with A/C in it, so I don't know what I am looking for. Is there one out there that uses the newest refrigerant, or are they all R134A?

Thanks a lot for your help in advance!!

Tim

PS - Yes, I know the grille is not the right one for that truck - it's already been swapped out with the right one, just haven't taken a new pic yet!!

Tim
Just came across this post. Attached are the diagram for your A/C system and the parts list from a 1985 parts manual. C60 is your standard A/C, C69 is overhead A/C. Sounds like you are looking for parts #8 and #9. Those tubes were not listed in the 1985 parts manual. This tells me they were not serviced separately. Best bet is probably to scrounge the bone yards for the parts from a 76-78 truck.
Butch

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[ChuckN]

Welcome from Oregon. Dig that visor stuff lol

I was gonna say, I dig the visors retro look on the 80s build 4x4s.

Welcome from the NW Washington. Nice rig!

 

[BigT]

Tim
Just came across this post. Attached are the diagram for your A/C system and the parts list from a 1985 parts manual. C60 is your standard A/C, C69 is overhead A/C. Sounds like you are looking for parts #8 and #9. Those tubes were not listed in the 1985 parts manual. This tells me they were not serviced separately. Best bet is probably to scrounge the bone yards for the parts from a 76-78 truck.
Butch

Thanks, Butch, that's very helpful! I sent photos of everything I have to Joe Neel at Old Air Products in Fort Worth, and he said it looks like I have everything I need except the compressor itself, which I'll be ordering from him in the next month or so. So maybe I don't need that part in the LMC diagram after all. I even found the stock upper and lower brackets on ebay (one NOS!), so I should be G2G!! When I start on it, I'll have to post some pics. It's going to include swapping the headers out for stock manifolds so I can use the stock lower bracket (plus I hate these leaky bastard headers) and putting all new dual exhaust on to fit the manifolds. Should be interesting, as I've never done an A/C system before.

 

[BigT]

I was gonna say, I dig the visors retro look on the 80s build 4x4s.

Welcome from the NW Washington. Nice rig!

Me too, Chuck! I'm planning to keep it on there.

 

[83 Box]

Welcome and gongrats on your "new" daily.
With respect to your rear end and a possible ratio swap, it would help to know if it is a 12-bolt or 10-bolt rear housing. I would bet that it is 12 bolt. I have very little experience with 12-bolt. In 10-bolt housings, different ratio ranges (3.08 through 3.23, etc) will only fit in certain housings. I learned this the hard way and it was expensive. Be sure to do some homework before spending any money.

 

[BigT]

Welcome and gongrats on your "new" daily.
With respect to your rear end and a possible ratio swap, it would help to know if it is a 12-bolt or 10-bolt rear housing. I would bet that it is 12 bolt. I have very little experience with 12-bolt. In 10-bolt housings, different ratio ranges (3.08 through 3.23, etc) will only fit in certain housings. I learned this the hard way and it was expensive. Be sure to do some homework before spending any money.

Yes, it is a 12 bolt full floater. I've been fortunate enough to find another complete rear end with 3.73 gears in it to swap it with. The drawback is that someone cut the spring perches off of it and the shock mounts are in the wrong place for my truck, so now the question is whether to move the shock mounts and weld on new perches and just swap the whole diff, or just swap the good guts into my existing housing. If I swap the guts, it gives me the opportunity to go through it all and put in new seals and bearings as well, although the ones in my current rear end are basically new - save for the leaky pinion seal. However, a straight full diff swap would probably be faster and easier, though I would do the bearings and seals in that one, too, before I swapped them. I am having a tough time deciding which to do.

For the Dana 44 front end I already have the new 3.73 ring and pinion gears, just need a new carrier and bearing/seal kit and I can do that one, too.